[Bug]: Codex child-agent output floods the parent chat

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

1. Start T3 Code and connect the Codex provider.
2. Open a project thread.
3. Ask: “Start 3 parallel sub-agents and summarize their results after they finish.”
4. Observe the parent chat and Agents panel.

Expected behavior

The parent chat should show only the coordinator’s messages. Child-agent
activity should appear separately in the Agents panel with readable names,
statuses, and token usage.

Actual behavior

Child agents’ narration, reasoning, commands, and tool output appear directly
in the parent chat. The conversation becomes flooded, and the Agents panel may
show no agents or only opaque UUIDs.

Impact

Major degradation or frequent failure

Version or commit

Local source build, based on main @ 02f4ce56

Environment

Fedora Linux, Brave browser, Codex provider, T3 Code source build

Logs or stack traces

Screenshots, recordings, or supporting files

before.png
after.png

Workaround

No reliable workaround. Reducing the number of parallel agents avoids the issue but defeats the multi-agent workflow.

Start in apps/server and reproduce the three-parallel-sub-agent scenario with the Codex provider. Trace how child-agent narration, reasoning, commands, and tool output are routed to the parent chat and Agents panel; done means only coordinator messages appear in the parent chat while agents show readable names, statuses, and token usage.